Cable Rehabilitation Program Second Responder Cable Treatment Program

Cable Rehabilitation Program (Second Responder Cable Treatment Program) By Lee Maurer Maintenance Planning SWEDE Conference April 26, 2011 - Bastrop, Tx

Oncor System Overview 27, 000 Square Miles of Territory 630 miles 3. 2 Million Electric Service Points 3, 000 Circuits Miles of Underground Primary (Networks not included) 390 miles § 17, 218 Cable Miles – URD § 4, 641 Cable Miles – Feeder § 21, 859 Total Miles of Overhead Primary § 10, 608 Mainline Primary § 13, 026 3ø Non-Mainline § 5, 006 2ø Lines § 27, 212 Single Phase Lines § 55, 852 Total Miles LM- Maintenance Planning 11

Cable Components Pre-1990 Tinned Copper Insulation Concentric Neutral Shield XLPE or HMWPE Insulation Since 1990 TRXLPE Insulation Aluminum Conductor Conventional Conductor Shield LM- Maintenance Planning Jacket Bare Copper Concentric Neutral Insulation Shield Aluminum Conductor (Strand-filled) Super Smooth Conductor Shield 2

Primary Underground Cable (Network Excluded) Previous specification cable Current specification cable 3

Primary Cable Faults LM- Maintenance Planning 4

Cable Rehabilitation Program - Background § System wide maintenance plan (Second Responder) for extending the life of aging infrastructure § Pre-1993 PE cable issues § 8, 000 cable miles – Pre-1993 PE cable – 7, 000 cable miles – URD – 1, 000 cable miles – Feeder § Cable Manufacture 1980 - 1995 – General Cable, Hendrix, Pirelli (Now Prysmian), Southwire § Capital Rehabilitation method for aged cable – 235 cable miles rehabilitated (By Utilx) § Cost effective alternative to replacement of cable § Additional 600 cable miles rehabilitated in other programs LM- Maintenance Planning 5

Second Responder Process When a cable faults, the troubleman (first responder) determines if the cable is loop fed and if the faulted cable can be switched out. Padmount Transformer Pole Riser Normal Open Point Fault Isolated Faulted Cable LM- Maintenance Planning 6

Second Responder Process (cont’d) § If the cable can be switched and service restored to the customers, the location of the faulted cable is sent to Oncor Program Services. § Program Services will then schedule a Utilx cable repair/rehabilitation crew to the cable. § The crew will attempt to repair and inject the cable with rehabilitation fluid. LM- Maintenance Planning 7

2 nd Responder Process § 4, 291 sections of failed cables came through the process since 2008 – 65% were able to be injected successfully. § 235 cable miles have been rehabilitated using 2 nd responder process since 2008. LM- Maintenance Planning 8

Business Comparison § Cable Repair - Splicing $X – O&M Cost – Same old cable § Rehabilitation of Span $ 4 X – Capitalized Cost – Added 20+ years of life § New Cable (Bore) $ 15 X – Capitalized Cost – New 40+ year asset LM- Maintenance Planning 9

Business Considerations that Prevent Rehabilitation § Cable installed in conduit (except preventative) § Corroded concentric neutral of 25% or less remaining § The faulted cable section must not have been deenergized more than six months. § There cannot be more that one joint per 100 feet of cable. (Business Case) § Other Technical Reasons – Butyl rubber cable – Cable with tape conductor shield – Loss of insulation shield conductivity – Insulation shield with no adhesion LM- Maintenance Planning 10

Questions Oncor Contacts Lee Maurer Senior Manager Mark Darilek Project Manager Mike Sulak Program Manager Richie Harp Consulting Engineer Maintenance Planning Operations/Program Services Distribution Standards 817 -215 -6128 lee. maurer@oncor. com 817 -215 -6809 mark. darilek@oncor. com 817 -215 -6151 michael. sulak@oncor. com 817 -215 -6008 rharp@oncor. com Fort Worth, TX 11